net/data/websocket/connect_check.html - cobalt - Git at Google

 <!DOCTYPE html>
 <html>
 <head>
 <title>test ws connection</title>
 <script type="text/javascript">

 var pageConnection = new Promise((resolve, reject) => {
   var protocol = location.protocol.replace('http', 'ws');
   var url = protocol + '//' + location.host + '/echo-with-no-extension';
   var ws = new WebSocket(url);

   ws.onopen = resolve;
   ws.onclose = reject;
 });

 var workerConnection = new Promise((resolve, reject) => {
   let worker = new Worker('./connect_check_worker.js');
   worker.onmessage = event => {
     if (event.data === 'PASS') {
       resolve();
     } else if (event.data === 'FAIL') {
       reject();
     }
   };

   // Start the worker.
   worker.postMessage('');
 });

 Promise.all([pageConnection, workerConnection]).then(() => {
   // Set document title to 'PASS'. The test observer catches this title changes
   // to know the result.
   document.title = 'PASS';
 }, () => {
   // Set document title to 'FAIL'.
   document.title = 'FAIL';
 });

 </script>
 </head>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<title>test ws connection</title>
	<script type="text/javascript">

	var pageConnection = new Promise((resolve, reject) => {
	var protocol = location.protocol.replace('http', 'ws');
	var url = protocol + '//' + location.host + '/echo-with-no-extension';
	var ws = new WebSocket(url);

	ws.onopen = resolve;
	ws.onclose = reject;
	});

	var workerConnection = new Promise((resolve, reject) => {
	let worker = new Worker('./connect_check_worker.js');
	worker.onmessage = event => {
	if (event.data === 'PASS') {
	resolve();
	} else if (event.data === 'FAIL') {
	reject();
	}
	};

	// Start the worker.
	worker.postMessage('');
	});

	Promise.all([pageConnection, workerConnection]).then(() => {
	// Set document title to 'PASS'. The test observer catches this title changes
	// to know the result.
	document.title = 'PASS';
	}, () => {
	// Set document title to 'FAIL'.
	document.title = 'FAIL';
	});

	</script>
	</head>
	</html>